Inclusion Criteria:
1. Provision of signed and dated informed consent form
2. Stated willingness to comply with all study procedures and availability for the duration of the study
3. History of type 1 diabetes for at least one year
4. Age 18-45 years
5. HbA1c \<10%
* BMI 18-35 kg/m2. Within this criterion, participants must have either BMI ≥25 or total daily insulin dose of ≥0.5 units/kg/day.
* Currently utilizing closed-loop AID therapy that is compatible with Dexcom G7 CGM.
* On stable regimen of non-diabetic medications for the last 6 months.
* All screening labs within normal limits or not clinically significant.
* Ability to take oral medication and be willing to adhere to the study drug/placebo for 12 weeks.
* For females and males of reproductive potential: agreement to use adequate contraception during study participation and for an additional 2 weeks after the end of CIR-0602K administration.
* For males of reproductive potential: use of condoms or other methods to ensure effective contraception with partner during study intervention.
* Agreement to adhere to Lifestyle Considerations throughout study duration.
Exclusion Criteria:
* Current Pregnancy or currently breastfeeding.
* History of smoking tobacco products within the last two years.
* History of alcohol abuse or illicit drug abuse within 6 months of screening.
* Known history of human immunodeficiency virus (HIV).
* History of other significant disease (e.g., cardiac, cerebrovascular, gastrointestinal, liver, renal, or endocrine) that could, in the investigator's view, alter study outcomes
* Any surgical or medical condition which may significantly alter the absorption of the study drug including but not limited to the following: history of major gastrointestinal tract surgery such as gastrectomy, gastroenterostomy, bowel resection, gastric bypass, gastric stapling, or gastric banding, currently active inflammatory bowel syndrome.
* Current use of any antihyperglycemic medication beyond insulin (i.e., GLP-1 receptor agonists, SGLT2 inhibitors, etc.).
* Unstable doses (i.e., dose change within the last 4 months) of vasoactive medications (e.g., calcium-channel blockers, statins, angiotensin-converting enzyme inhibitors, diuretics, nitrates, alpha-blockers, beta-blockers, etc.).
* Daily use of anti-inflammatory medications (e.g., ibuprofen, aspirin, prednisone, dexamethasone, etc.).
* Diagnosis of peripheral neuropathy (assessed by screening monofilament exam).
* Macroalbuminuria (i.e., urine albumin: creatinine \>300 mg per g).
* Retinopathy beyond mild, nonproliferative retinopathy.
* History of Level 3 hypoglycemia within the last 12 months.
* History of diabetic ketoacidosis (DKA) within the last 12 months.
* Screening electrocardiogram (ECG) findings indicative of arrhythmia, sinus node disease, or ischemic heart disease.
* Screening oxygen saturation \<90%
* History of hypersensitivity or prior adverse reaction to the study drug, closely-related compounds, or any of the stated ingredients.
* Use of concomitant medications with a known significant metabolism by CYP2C8 or CYP2C (including paclitaxel, phenytoin, warfarin, celecoxib, tolbutamide, or repaglinide) for the duration of the study.
* Participation in an investigational study (other than a non-treatment registry study) or received an investigational drug withing 30 days or 5 half-lives (whichever is longer) prior to randomization.
